This invention relates to a sight scope used for a rifle gun, an archery and the like.
In general, a sight scope includes a sleeve-like scope body. This scope body has an objective lens system at a front end portion thereof and an eyepiece lens system at a rear end portion thereof. An erect sleeve is received in the scope body. An erect lens system is disposed within the erect sleeve so that the shooter can see a target as an erect image.
As disclosed in Japanese Laid-Open Utility Model Application No. Sho 59-94318, the erect sleeve is inclinably supported at its end portion on the side of the eye piece. The erect sleeve is inclined upwardly and downwardly with respect to the axis of the scope body by an inclination adjusting mechanism, depending on a distance from the shooter to the target. Consequently, the target image is adjusted in relative position with respect to a reticle image. Also, this inclination adjusting mechanism is operated to incline the erect sleeve rightwardly and leftwardly depending on intensity of wind power.
The inclination adjusting mechanism comprises an adjusting member threadedly engaged with a scope body and a spring for biasing that end portion of the erect sleeve which is located on that side of the objective lens, so that the elect sleeve is brought into abutment with an inner end of the adjusting member. The inner end of the adjusting member is defined as a flat surface, while an outer peripheral surface of that end portion of the erect lens which is located on the side of the objective lens, is defined as a cylindrical surface.
The shortcomings of the inclination adjusting mechanism thus constructed will be described with reference to FIGS. 8A, 8B and 8C. In those illustrations, a peripheral wall of the scope body is represented by reference numeral a; the erect sleeve, by b; the adjusting member, by c and an axis of the scope body a, by L, respectively. As shown in FIG. 8A, when the adjusting member c is in a neutral position, the erect sleeve b is coaxial with the scope body a. Consequently, an inner end face of the adjusting member c is in line-contact with the scope body a along the axis L. As shown in FIG. 8B, when the adjusting member c is in a retreated position with respect to the scope body a, the erect sleeve b is inclined upwardly. Consequently, the adjusting member c is in contact with the erect sleeve b at a point x. In contrast, as shown in FIG. 8C, when the adjusting member c is inserted deep into the scope body a, the erect sleeve b is inclined downwardly. Consequently, the adjusting member c is in contact with the erect sleeve b at a point y. In this way, if the inclination direction of the erect sleeve b is different, the erect sleeve b and the adjusting member c are in contact with each other but at a different contacting point. Accordingly, a distance between a pivotal point of the erect sleeve b and the contacting point is varied. As a consequence, a relation between an amount of axial movement (in other words, an amount of pivotal operation) of the adjusting member c and an angle of inclination of the erect sleeve b is varied depending on the inclination direction of the erect sleeve b. The reason is that the angle of inclination is determined by the distance between the pivotal point of the erect sleeve b and the contacting point and the amount of movement of the adjusting member c.